In conventional wireless mobile communications, roaming agreements typically exist between network operators of respective public land mobile networks (PLMNs). Such roaming agreements permit a mobile subscriber unit based in a first PLMN to use the services and facilities of a second PLMN while the mobile subscriber unit is roaming in the coverage area of the second PLMN, outside the coverage area of the first PLMN.
Call forwarding (CF) is one example of a service that a roaming mobile subscriber might wish to use while roaming in the second PLMN. Using the conventional GSM (Global System for Mobile communications) network as an example of the first and second PLMNs, in a conventional GSM network the cost of forwarding (or otherwise deflecting) a call is charged to the mobile subscriber which invoked the forwarding. If the mobile subscriber is roaming internationally, then the forwarding of a call will very likely be charged, disadvantageously, as an international call. Paying international call charges to forward a call is typically very expensive.
Call deflecting service is similar to call forwarding, except the mobile subscriber interactively chooses (on a per call basis) to deflect the call to another destination rather than accept the call, whereas call forwarding services are typically handled in the serving mobile switching center (MSC) without interaction of the mobile subscriber. The problems and inventive solutions disclosed herein apply to both call forwarding and call deflecting services.
Another problem with forwarding the calls of the above-described roaming mobile subscriber is fraud. Call forwarding fraud during roaming occurs when the mobile subscriber uses call forwarding service to forward calls received while the mobile subscriber is roaming internationally, but for which the roaming mobile subscriber does not intend to pay the corresponding international charges. Such fraud can be increased by maintaining several simultaneous calls after invocation of the call forwarding service. The same scenario can occur using call diversion service. This fraud problem is very costly for network operators due to the international signaling links and call legs involved during the calls. In fact, fraud is such a large scale problem that network operators in some countries refuse to provide services such as call forwarding services to mobile subscribers roaming in those countries.
In GSM, there are some conventional mechanisms for cost limitation when the mobile subscriber is roaming. For example, an operator determined bar (ODB) can be applied to outgoing calls originating at the mobile subscriber unit, including calls to be forwarded, such that the invocation of call forwarding services is barred. The ODB in GSM also provides for different restriction levels, for example, barring all calls, all international calls, all international calls except those directed to the mobile subscriber's home PLMN country, all inter-zone calls, or all inter-zone calls except those directed to the subscriber's home PLMN country. However, this solution will disadvantageously bar even outgoing calls for which the mobile subscriber consciously intends to pay the incurred cost.
Another possible solution to the above-described call forwarding problems is simply for the mobile subscriber to deactivate the call forwarding services. However, the subscriber may well forget to deactivate the services when roaming internationally. Moreover, deactivation of call forwarding does not address the fraud problem described above.
Call forwarding can be barred using conventional Regional Services functionality, but only by disadvantageously deregistering the mobile station from all services to which it subscribes whenever that mobile station enters the service area of a disallowed MSC. Moreover, this type of service must be implemented in the MSC/VLR and can only be used if the Regional Services functionality is implemented in the PLMN where the subscriber is roaming.
Another possible approach would be to use Intelligent Network (IN) architecture to implement services aimed at solving the above-described problems. However, disadvantageously, the Intelligent Network support must be requested in the PLMN where the subscriber is roaming.
It is therefore desirable to provide to a roaming mobile subscriber call forwarding (or deflecting) service with automatically activated security against large, unwanted charges for forwarding/deflecting calls without barring all of the mobile subscriber's outgoing calls.
The present invention provides for selective barring of call forwarding/deflecting services. The selective barring is triggered by the location of the mobile subscriber unit, thereby avoiding the occurrence of many unwanted call forwarding/deflecting charges when the mobile subscriber unit is roaming, and all outgoing calls need not be barred.